Can a 1 month old rabbit be with a 3 year old rabbit?

One-month-old rabbits are just starting to wean, so they should still be with their mother for at least another two weeks.

Rabbits are unique creatures. Their minds work differently than ours do; but, like us, they are individuals and sometimes get along or don't get along with others for individual reasons. A baby rabbit can get along with a grown-up rabbit, but that doesn't mean all babies and grown-ups will get along.

Rabbits shouldn't be put together if they aren't "bonded" because rabbits do sometimes fight, and when they fight they can seriously injure each other so they shouldn't be allowed to fight, ever (even the smallest bite or cut can turn into an infected abscess). There are steps you can take to try to bond two rabbits together. See the related links below for help.

Breeding is a different story. Rabbits reach sexual maturity between 3 and 8 months; a rabbit younger than 3 years old isn't old enough to have babies.